The present invention relates to a method of inserting and fixing or clinching electronic components (hereinafter called component) to a printed circuit board (hereinafter called p-c-b for short) and an apparatus for practically realizing the method.
The general process order of inserting or planting components to a p-c-b is (a) inserting a pair of lead wires of a component into lead wire inserting holes (hereinafter called simply inserting holes) formed, large in number, over the surface of a p-c-b; (b) bending or clinching a portion of the lead wires protruded to the back of the p-c-b, passing through the holes, for preventing the same from coming off; and then soldering the lead wires to the conductive circuit arranged on the p-c-b.
Recently developed automatic planting methods of components and apparatuses therefor have greatly contributed to the rationalization of assemblying lines, not only in the field of household electrical appliances such as television sets, audio apparatuses, etc., but also in the field of industrial instruments and machines. Most of the conventionally utilized means or apparatuses for this purpose have been, however, based on employing of an inserting guide having tapered guide holes or inclined guide grooves. After a component-to-be-inserted having been moved to targeted holes by a separate means such as a chuck or a pusher, the tip of the lead wires of the component-to-be-inserted are guided to the targeted inserting holes by the above-mentioned inserting guide. These inserting guides are mostly usable for only one type of component having a specific lead wire gage (the distance between the two lead wires). In actuality, the lead wire gage is of much variety, such as 1.5, 2.0, 2.5, 5.0, 6.0 mm--(there are many standardized dimensions). In the conventional way of planting the components on the p-c-b, one type of components of a specific gage have to be planted first, scatteringly with much interval, and another type of components of a different gage must be planted with another inserting guide between the already planted components. Such being the case, components-to-be-inserted of different gage dimension require changing inserting guides every time according to the size of the components one by one sporadically over the surface of the p-c-b, seeking enough space available for the planting operation. The more the planting stage advances, i.e., as the planting operation progresses, the harder becomes the planting operation, because the p-c-b surface is filled with the already planted components, requiring seeking space in the scantily left area. In other words, the conventional way of planting is faulty in that it is inefficient in its operation because of the need to change the guide often and seeking an operation space with difficulty, and that consequently the distribution density of planting is comparatively low. For some components of so-called axial type wherein the lead wires are extending axially from either side of a component, a device which is disclosed by the Japanese Published Examined patent application No. 49 (1974)-7936, is known. This device is able to plant or insert the lead wires bent at a right angle, even when the gage or distance of the lead wires are different in several dimensions. This device is composed of two parts for inserting respectively the right side wire and the left side wire, and is obliged to be complicated in its construction, because it aims at planting components of different gage by means of adjusting the distance between the two parts of the device itself. Such a device is a step progress indeed, but it is too expensive because of its sophisticated structure, to be generally utilized, and still leaves something to be desired because of its non-applicability to components of so-called radial type wherein the lead wires are extending parallelly at one side of a component. This invention has been made from such a background.
It is therefore a primary object of this invention to provide a technological art of inserting for fixing a plurality kinds of components, different respectively in the lead wire gage, at as high a distribution density as possible, into the inserting holes in a p-c-b.
It is another object of this invention to provide a technological art of inserting for fixing a plurality of kinds of components, different respectively in the lead wire gage, with a desired order, into the inserting holes in a p-c-b.
This invention, in order to fulfill the above-mentioned objects, is aimed at (a) chucking the two lead wires of a component by means of a chuck, which is open and closable between the two pawls thereof in a perpendicular direction to a plane determined by the two lead wires, with a distance identical to that between a pair of lead wire inserting holes formed in the p-c-b; (b) letting the lead wires protrude from the chuck by means of a separately disposed pusher, or approaching the chuck itself with the lead wires held to the p-c-b; and (c) inserting the lead wires into the inserting holes and clinching the projected portion of the lead wires to the back side of the p-c-b by bending or squashing.
Regarding this chucking operation of the lead wires there are several unprecedented devices applied here. One of which is, in chucking a variety or plurality of kinds of components having respectively different wire gage indiscriminately, to chuck one of the lead wires at a preset base position of the chuck biased to either one edge of the chucking surface thereof (selectable either one edge from both edges). When the inserting is about to take place, the p-c-b is rightly positioned relative to the chuck such that the already planted component just comes to the side of the very edge of the chuck at which edge the lead wires of the component-to-be-inserted are held. In case of chucking and inserting such lead wires by a chuck, which is open-and closable in a direction perpendicular to the plane including the two lead wires, a chuck having a width of the chucking portion wider than the widest lead wire gage of the components, is able to cover all the components-to-be-planted. Such a chuck would be too big in size, when used for planting comparatively small sized components of narrower gage, and consequently requires too much useless space around the components. It would also produce another problem of degrading the distribution density of component planting. This invention has solved this knotty problem by a principle that the chucking of lead wires is always done by holding a pair of lead wires at either one or exclusively one biased edge portion of the chuck, instead of holding at the central portion thereof, and by always letting this biased edge portion approach the already planted component through an appropriate relative positioning of the chuck and the p-c-b. By means of such an arrangement of the chuck, the portion thereof where it does not hold the lead wires is always positioned above a non-planted area of the p-c-b, which provides no disadvantageous conditions with respect to distribution density. Although this invention was made focusing on planting of the components of radial type, it may be applicable to those of axial type, too, so long as the lead wires (or one of the lead wires) are bent in advance to extend parallelly with a preset distance to each other.